The present invention relates generally to the field of pressure assist water closet systems, and more particularly, to a pressure assist flush system for use with in-wall plumbing that is easy to service.
U.S. Federal Law currently requires that water closet systems do not exceed 1.6 gallons per flush (1.6 gpf). This standard has posed certain difficulties for standard gravity flush toilets. A gravity flush toilet relies on a combination of head pressure of the water in the holding tank and siphonic action in the trapway to provide the force to evacuate waste from a bowl. In order to meet the 1.6 gpf standard, new bowls include reduced trap size and reduced standing water surface area.
A pressure assist water closet system stores water under pressure to provide thrust to discharge the contents of a bowl during a flush cycle. The pressure is supplied by the pressure in the water supply line itself and no additional power is required. The water enters the storage vessel and trapped air is compressed. Since a liquid is non-compressible and air is compressible, the air will be compressed until the air pressure in the vessel is equal to the water supply line pressure. The pressure in the tank can be set not to exceed a certain value with a pressure regulator.
When the bowl is ready to be flushed the water in the vessel is released under pressure into the bowl, thereby thrusting the waste out of the bowl.
A pressure assist flush system provides a number of advantages over a traditional gravity flush system. First, the discharge pressure of the water is greater than that achieved in gravity assist units. The increased pressure allows for greater evacuation with less water by thrusting the waste out of the bowl. The pressurized water enables the use of discharge line with a greater diameter and greater surface area of standing water within the bowl.
Various pressure assist flush systems and improvements are described in U.S. Pat. No. 4,233,698 entitled “Pressure Flush Tank For Toilets” to Martin; U.S. Pat. No. 5,361,426 entitled “Hydraulically Controlled Pressurized Water Closet Flushing System” to Martin; U.S. Pat. No. 5,970,527 entitled “Pressurized Water Closet Flushing System” to Martin et al.; U.S. Pat. No. 6,360,378 entitled “Pressurized Water Closet Flushing System” to Martin; and U.S. Pat. No. 6,343,387 entitled “Volume Control For A Water Closet” to Beh. Each of these patents are incorporated herein by reference.
An increasing desire in plumbing construction is to place the closet water tanks within the bathroom walls. The in-wall system can be serviced through an access panel located on the wall. Any failure of the water tank system requires the ability to access the unit for repair or replacement. The reliability of pressure assist systems and the sealed environment of the vessels of the pressure assist units provide an ideal system for in-wall plumbing. However, since the access panel will provide a limited area in which to service any in-wall unit, it would be desirable to be able to easily access all of the components of the water tank system. Further, since the tank will be supported within the wall it would be desirable to provide a tank or vessel to minimize the pressure placed on the various components to reduce the number of component failures. It would also be desirable to provide a system that would fit within the envelope between the studs and walls of standard construction. It would further be desirable to provide fill and discharge tubes that remain within the vessel when servicing certain components of the pressure assist system. It would also be desirable to provide a controlled pressure relief valve to prevent damage to the device should a repair technician fail to properly depressurize the device prior to servicing the pressure assist unit. Given the tight envelope to service the pressure assist unit, it would be desirable to remove components from the vessel without tools. It would also be desirable to test components of the system outside of the wall environment and independent of the vessel why still hooked up to the in-wall plumbing.